The huge Hongqi Bridge in China’s Sichuan province, touted as a major achievement in China’s infrastructure boom, collapsed into the river it once spanned on Tuesday.

Fortunately, local officials noticed ominous cracks in the 2,500-foot span on Monday and closed it to traffic, so there were no casualties reported when it came down.

The Hongqi Bridge was completed in January as part of an ambitious program to improve the G317 national highway, which leads from Sichuan to Tibet. Construction was handled by a Chinese state-backed firm called Sichuan Road & Bridge Group.

The mountainous region where the bridge was located is seismically active, and experienced a devastating earthquake in 2008 that killed almost 70,000 people.

The bridge was only open to traffic for a few months before police and transportation officials in the nearby city of Ma’erkang discovered cracks in the road near the bridge. Landslides were reported in the area on Monday, prompting officials to close the bridge and establish a detour.

The demise of the Hongqi Bridge on Tuesday afternoon was spectacular, as huge sections of the heavy concrete span fell hundreds of feet into the river gorge below, kicking up enormous plumes of dust:

The exact cause of the bridge’s collapse is still under investigation. Local landslides seem to have played a role, and geological instability – perhaps even small earth tremors – could have dealt the final blows to the structure.

“The sudden collapse has raised concerns over the quality of China’s construction and whether sufficient geological surveys were carried out. Local authorities are attempting to downplay the incident, describing it as an isolated natural event,” the UK Telegraph reported on Wednesday.